Field of the Invention
The present invention is directed to a method and system for inspecting structures for hidden defects and damage, and more particularly, to a method and system for displaying detected defects on a three-dimensional representation of a structure or a portion or element thereof.
The condition of structures such as single family homes, apartments, and commercial buildings is evaluated, or estimate when, for example, the building is sold, and/or used as collateral for a loan. The evaluation or estimation typically includes an inspection of the building. A major reason for the inspection, particularly for wood-framed homes and commercial buildings, is that the building may have been damaged by wood-eating insects, such as, for example, termites, or by wood damaging fungus, commonly called “wood rot.” The damage is often hidden because wood frames are almost always concealed by, for example, drywall, paneling, clapboard, brick and other wall surface materials. Therefore, neither the existence of the damage, nor its extent, is generally visible without removing the covering material. In other words, an accurate determination of the existence of, and full extent of termite or wood rot damage to a typical wood-framed house or other wood-framed structure would require removing all of the wall covering, thereby rendering the entire frame visible. However it is generally not feasible, either practically or economically, to remove all the wall covering of a house or commercial building each and every time damage, such as termite or wood rot, requires assessment. This would essentially require destruction and rebuilding of a house each time its value needed accurate assessment.
Prior art methods exist for detecting damage caused by termite actively. One such method is acoustic emission detection, which senses the vibrations produced by termites when they break the cellulose and lignin fibers, i.e., eat the wood they are consuming, as described by, for example U.S. Pat. No. 4,895,025 issued Jun. 26, 1990. U.S. Pat. No.5,285,668 in the name of Robbins and Mueller describes another system for detecting wood-destroying insects by sensing acoustic emissions.
There are multiple shortcomings with the known acoustic emission methods. One is that acoustic emission techniques are prone to error due to ambient noise. Another is that termites are not always feeding. Still another is that termites may use extensive galleries to move between a feeding region and a nest, and acoustic emission methods may not detect termites within such galleries. A still further, and more significant shortcoming is that acoustic emission methods detect only the presence of feeding termites; they do not detect, much less give an accurate assessment of, the damage that the termites have caused in the past or damage produced by wood rot or resulting from other non-insect causes.
For the reasons above, building inspectors typically compromise by removing only a portion of the wall covering when performing an inspection or damage assessment. This practice of partial removal has two untoward effects. One is that even though the removal is limited there is still some damage to the building. A second, and perhaps more important negative effect is that significant damage may be overlooked. Therefore, the result of the partial removal is that either a buyer is faced with major repairs, or a lender is faced with a building having less collateral value than originally estimated.
Another shortcoming of existing methods is that the building inspector typically describes location and extent of the termite or wood rot damage verbally or using sketches. Rarely does an inspector have access to the complete architectural drawings of the house on which he could mark damaged areas to enable others to visualize the extent of the damage.
Still another shortcoming of existing inspection methods is that once a wood framed structure is completed it is virtually impossible to verify the integrity of the original construction methods through nondestructive means, e.g., it may be difficult or impossible to determine the fastener pattern used for securing the wall material to the underlying supports or studs and whether an adequate number of fasteners was used.